While combination brake lights and interior lights for mounting in the rear door of a pick-up truck cap have not previously been provided, combination lighting devices have been disclosed for use on the trunk lids of passenger cars. For instance, U.S. Pat. No. 2,221,178, issued Nov. 12, 1940, to Frank C. Best, shows a signal device which provides a brake light which is located near the center of the trunk lid in combination with a tail light and a means for illuminating the license plate. Further, the same lamp which illuminates the license plate and the tail light illuminates the interior of the trunk, at anytime that the tail lights are energized. No arrangement is provided for discontinuing the illumination of the trunk when the trunk lid is closed. Further, the signal device is neither adapted nor does it suggest a mechanism for adapting it for mounting on a truck cap door. Other combination vehicle lights, similar to that shown in the Best patent, are shown in U.S. Pat. No. 2,054,919, issued Sept. 22, 1936, to Benjamin H. Anibal, and in U.S. Pat. No. 2,736,005, issued Feb. 21, 1956, to Charles L. Craddock.
It is an object of the present invention to provide a combination supplemental brake light and interior light for mounting on the rear door of a truck cap, which brake light is readily visible to vehicles following the pick-up truck, and which interior light is automatically energized, unless disabled, upon opening of the cap rear door.